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What is Talzenna™(talazoparib tosylate)?

Talzenna™ (talazoparib tosylate) is a medication that is approved to treat adults with metastatic or locally advanced HER2- breast cancer, who also have one of the BRCA gene mutations that often lead to breast cancer. BRCA1 and BRCA2 mutations account for about 5-10% of breast cancer cases in US women.

People with BRCA1 or 2 gene mutations inherit them from their families. The normal function of these genes is to help repair DNA, the molecular instruction manual inside every cell in the body. When DNA accumulates mistakes or mutations, the cells that contain these mistakes can become cancerous and multiply without stopping. People without adequate protection against mistakes in their DNA are at increased risk of developing cancer. About 50-85% of people with BRCA1 or 2 mutations will develop breast cancer by age 70.4

Breast cancer tumors can be characterized as HER2+ or HER2- cancers. HER2 refers to a particular protein that appears on the surface of cancer cells and makes the cells multiply faster. When cancer cells produce too many HER2 molecules, they are referred to as HER2+ tumors. HER2- cancers produce few or no HER2 molecules. Locally advanced breast cancer is cancer that has spread beyond the breast, to the chest wall, skin, or lymph nodes, but it has not spread to other parts of the body. Metastatic breast cancer has spread to other parts of the body.

What are the ingredients in Talzenna?

The active ingredient in Talzenna is talazoparib tosylate.

How does Talzenna work?

Talzenna is a poly (ADP-ribose) polymerase (PARP) inhibitor. PARP is a molecule that is particularly important in repairing the DNA of cells with BRcA1 and BRCA2 mutations. Talzenna binds to PARP molecules, which prevents them from working properly. This allows breast cancer cells to accumulate DNA mutations, which eventually kills them.

What are the possible side effects of Talzenna?

Common side effects with Talzenna include:

  • Tiredness or weakness
  • Low numbers of red or white blood cells
  • Nausea
  • Low number of platelets, which help stop bleeding
  • Headache
  • Loss of appetite
  • Vomiting
  • Hair loss
  • Diarrhea

In some patients, Talzenna may cause more harmful side effects. These include bone marrow problems called Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML). Some people with cancer who have previously been treated with chemotherapy or certain other cancer medicines developed MDS or AML during or after treatment with Talzenna. MDS and AML may be life-threatening. If you develop MDS or AML, your healthcare provider will stop treatment with Talzenna.6

Low blood cell counts are a common side effect of Talzenna, but they can be signs of a more serious problem. Tell your doctor if you experience extreme tiredness, weight loss, fever, frequent infections, blood in the urine or stool, bruising or bleeding, or shortness of breath.6 Talzenna has been shown to harm fetuses and to pass into breastmilk, so it is important not to become pregnant or breastfeed while you or any male partners are taking Talzenna. Talzenna has not been tested or approved in children.6

This is not a complete list of all potential side effects of Talzenna. For more information, consult your doctor or healthcare provider. If you notice any new or worsening side effects, contact your doctor or healthcare provider immediately.

Things to note about Talzenna

Before taking Talzenna, tell your doctor if you6:

  • Have kidney problems
  • Are pregnant or plan to become pregnant or are breastfeeding

Tell your doctor about any medications or supplements you are taking while on Talzenna, because it doesn’t mix well with certain medicines. It is important for doctors to test your blood cell counts before and regularly during therapy with Talzenna since it can cause serious, harmful reductions in blood cell numbers.15

Dosing information

Talzenna comes in a capsule-type pill that contains 1 mg of medicine. You should swallow one pill once a day, with or without food. It is important to swallow Talzenna capsules whole and not to dissolve or open them. Talzenna also comes in 0.25 mg capsules, so doctors can reduce your dose when it is time to stop taking the medicine or if you experience serious side effects.5 For more information about Talzenna, read the complete prescribing information.

Written by: Editorial Team | Last reviewed: July 2019.
  1. Karen Honey. FDA Approves a New PARP Inhibitor for BRCA-mutant Breast Cancer. American Association for Cancer Research. October 17, 2018. Available at: Accessed July 12, 2019.
  2. BRCA1 & BRCA2 Genes: Risk for Breast & Ovarian Cancer. Memorial Sloan Kettering Cancer Center. Available at: Accessed July 12, 2019.
  3. Tumor Characteristics: Hormone Receptor Status. Susan G. Komen Breast Cancer Foundation. January 31, 2019. Available at: Accessed July, 12, 2019.
  4. Locally Advanced or Inflammatory Breast Cancer. Susan G. Komen Breast Cancer Foundation. June 10, 2019. Available at: Accessed July 12, 2019. TALZENNA-talazoparib capsule.
  5. Daily Med. US National Library of Medicine. December 6, 2018. Available at: Accessed July 12, 2019.
  6. R Talzenna. Pfizer Oncology. 2019. Available at: Accessed July 13, 2019.